Devices for breaking down hard or rocky materials

ABSTRACT

A HYDRAULIC PISTON AND CYLINDER DEVICE FOR BREAKING HARD OR ROCKY MATERIAL BY DRIVING A WEDGE INTO A HOLE IN SAID MATERIAL, IS CARRIED BY A MANDREL INSERTABLE INTO SAID HOLE AND HAVING MEANS WHEREBY IT IS EXPANDED, BY OPERATION OF THE PISTON AND CYLINDER DEVICE, SO AS TO BECOME   SELF-HOLDING IN SAID HOLE AND FORM AN ANCHORAGE FOR THE DEVICE WHEN THE LATTER APPLIES A FORCE TO THE WEDGE TO DRIVE IT INTO THE HOLE.

Feb. 23, 1971 o. T. WALSH 3,565,433

DEVICES FOR BREAKING DOWN HARD 0R ROCKY MATERIALS Filed Jan. 17, 1969 INVENTOR:

OO/VALO THOMAS 11/41. SH,

5W, Mil M ATTORNEYS.

United States Patent 3,565,488 DEVICES FOR BREAKING DOWN HARD OR ROCKY MATERIALS Donald T. Walsh, Anderton, near Chorley, England, as-

signor to Wm. Park & C0. Forgemasters Limited, Wigan, Lancashire, England, a British company Filed Jan. 17, 1969, Ser. No. 792,084 Claims priority, application Great Britain, Feb. 24, 1968, 9,067 68 Int. Cl. E21c 37/08 US. Cl. 299-22 5 Claims ABSTRACT OF THE DISCLOSURE A hydraulic piston and cylinder device for breaking hard or rocky material by driving a wedge into a hole in said material, is carried by a mandrel insertable into said hole and having means whereby it is expanded, by operation of the piston and cylinder device, so as to become self-holding in said hole and form an anchorage for the device when the latter applies a force to the wedge to drive it into the hole.

This invention is for improvements in or relating to devices (for breaking down hard or rocky materials.

A particular application of the invention, which is mentioned by way of example, is to the winning or mining of minerals, e.g., coal, ore and the like.

In the working or mining of rock or mineral-bearing materials it is a common practice first to drill a hole into the material and then drive into the hole a wedge or drift which splits and breaks down the rock or ore. Driving-in of the wedge or drift is frequently effected by means of a hydraulic ram or the like, It is necessary to provide an abutment or reaction member against which the hydraulic ram can act so as to force the wedge or drift into the hole. This abutment or reaction member usually takes the form of a stake or strut secured in the floor or roof or between the floor and roof of the strata being worked.

Such an abutment or reaction member is open to the objection that it may slip or a large amount of the stroke of the hydraulic ram or other driving device is, so far as driving-in of the wedge or drift is concerned, uselessly, taken up in movement of the stake or strut until it bites or becomes fixed in the floor or root or therebetween. In other words, there may be insufiicient stroke of the hydraulic ram available to perform the task of splitting the rock mass.

An object of the present invention is to provide a device which dispenses with this inefficient form of abutment.

According to the present invention there is provided a device for breaking hard or rocky material by driving a tool into said material wherein the device is provided with a member insertable into a hole in said material and which is self-holding in said hole, so as to form an anchorage for the device, when the latter applies a force to said tool.

According to a further feature of the present invention there is provided a device for breaking hard or rocky material comprising a cylinder, a piston in said cylinder, a mandrel or sleeve insertable into a hole in said material, the piston and the mandrel having cooperating parts whereby movement of the piston in one direction, relatively to its cylinder, expands the mandrel to anchor it in said hole and means for supplying fluid-pressure to said cylinder so as to urge the piston in said direction and the cylinder in the opposite direction whereby an expanding tool interposed between the cylinder and the hole will be driven into the hole to break the material.

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The construction of the device may be such that as the force for expanding the hole and splitting or breaking down the material increases, the anchoring force for the device also increases and assists in breaking the material. Conveniently the wedge or drift which the device drives into the hole so as to expand it and split or break down the material in its vicinity has at least two different angles along its length to provide a cracking length and a dislodging" length.

For some purposes at least it is an advantage if the wedge or drift is a single wedge or is single-edged, the inclined face in use being set towards the free side of the rock mass to be broken.

The power source for operating the device to secure the anchoring means in a hole and drive in the wedge or drift may be a hydraulic ram, explosion chamber or similar device.

The device may also 'be equipped with means for extracting it from the hole in the material to be broken down. It will be appreciated in this connection that material may not be broken down for the full depth of the hole.

One particular embodiment of the invention will now be described, by way of example, with reference to the accompanying drawing.

The device shown on the drawing comprises a drawbar 10 slidable within a mandrel 12 and having a conical end 11. At least the forward part of the mandrel, where it is tapered to receive the conical end 11 of the drawbar, is split longitudinally. A lug 13 is provided on the end of the mandrel 12 remote from the conical end 11 of the draw-bar.

The end of the draw-bar 10, remote from its conical end 11, is attached, piston-rod fashion, to a piston 16 which works in a hydraulic cylinder 15. The cylinder 15 has a port 17 for pressure-fluid, on the retraction side of the piston 16 and a port 18 for pressure-fluid on the extension side of the piston. The draw-bar-cum-pistonrod 10 works through a gland 21 in the end of the hydraulic cylinder and the piston 16 is provided with a seal or piston ring 22.

A catch 19 is pivotally attached to a pushing part 20 of the ram cylinder 15.

In operation, the mandrel assembly 10, 11, 12 is inserted into the hole It previously drilled in the material to be split or broken down, the part 20 bearing on the lug 13. Pressure-fluid is then supplied to the cylinder 15 through the port 17, the port 18 being open to exhaust. This causes the draw-bar 10 to be retracted with respect to the split mandrel and, due to the conical end 11 of the draw-bar, the mandrel is expanded. Thus, the device is anchored firmly to the mass of material M. During this operation the catch 19 is swung upwardly so that it does not engage the lug 13.

When this anchoring or securing of the device in the rock has been completed pressure-fluid is supplied to the cylinder 15 through the port 18, the port 17 being open to exhaust. This retracts the cylinder 15 until the piston 16 is at its left-hand end.

A wedge 14, which has an arcuate inner face which embraces an arcuate extension 12a, of reduced diameter, of the mandrel 12', is then inserted between said extension and the wall of the hole 12. Fluid under pressure is again passed through the port 17 and the port 18 opened to exhaust. This forces the cylinder 15 to the left and drives the wedge 14 further into the hole h so as to split or break down the piece of rocky material indicated at M1. It will be noted that the wedge has two different angles along its length. Furthermore, the wedge is a single wedge, the inclined face being set towards the free side M2 of the rock to be broken.

Upon completion of the breaking cycle the catch 19, which has been brought into the position shown in the drawing, engages, or is put into engagement behind the lug 13 of the mandrel. Pressure-fluid is then fed through the port 18 for a short period, the port 17 being open to exhaust. This moves the piston 16 to the left in the cylinder 15 which is held by the catch 19. This movement of the piston withdraws the conical end 11 of the draw-bar sufficiently from the mandrel 12 to allow the latter to contract to facilitate withdrawal of the device from the hole It.

The device may have a two-part draw-bar 10 to suit holes of dilfering depths.

I claim:

1. A device for breaking hard or rocky material comprising a pressure fluid operated ram having relatively movable piston and cylinder members, an expandable anchoring mandrel to be inserted into a hole in said material, an expanding element for said mandrel driven by one of said members of said ram, and a rock breaking wedge to be inserted into said hole and between the latter and the other member of said ram whereby, when pressure fluid is supplied to the ram between said members thereof, the mandrel will be expanded in the hole to anchor the device to the material and the Wedge will be driven into the hole to break the material.

2. A device for breaking hard or rocky material as claimed in claim 1 wherein the mandrel is tubular and the expanding element therefor is a tapered part in said tubular mandrel and on an end of a piston rod of the piston member of the ram.

3. A device for breaking hard or rocky material as claimed in claim 1 wherein the wedge has at least two different angles along its length to provide the wedge 4 with a cracking portion and a dislodging portion for the material to be broken.

4. A device for breaking hard or rocky material comprising a cylinder, a piston in said cylinder, a piston rod on said piston and projecting from said cylinder, a tubular expandable mandrel positioned on said piston rod to be inserted therewith into a hole in said material, the piston rod and the mandrel having respectively a conical part and a tapered bore for said conical part whereby movement of the piston in one direction, relatively to its cylinder, expands the mandrel in said hole, means for supplying pressure fluid to said cylinder so as to urge the piston in said direction and the cylinder in the opposite direction, and a rock breaking wedge to be inserted in said hole and between the latter and the cylinder whereby when pressure fluid is supplied to the cylinder, the mandrel is expanded to anchor the piston rod in said hole and the cylinder acts on the wedge to drive it into the hole to break the material.

5. A device as claimed in claim 4 wherein the cylinder has means for anchoring it to the mandrel and also supply means for pressure-fluid for urging the piston in the opposite direction, relatively to its cylinder, whereby the mandrel is contracted to facilitate its withdrawal from the hole.

References Cited UNITED STATES PATENTS 94,216 8/1869 Jones et al. 29922 3,439,954 4/1969 Darda 299-22 FOREIGN PATENTS 245,615 4/1911 Germany 299-22 ERNEST R. PURSER, Primary Examiner 

